Pull down drive unit



J1me 1 MCKENZIE ,7M,8@

PULL DOWN DRIVE UNIT Filed May 16, 1951 2 Sheets-Sheet 1 INVENTOR. M H.M Kenzie June 2, 1955 Filed May 16, 1951 W. H. M KENZIE PULL DOWN DRIVEUNIT 2 Sheets-Sheet 2 JNVENTOR.

[ H. M Kenzie PULL DOWN DRIVE UNIT Walter H. McKenzie, Tulsa, Okla.,assignor of one-fourth to George W. Reed, Tulsa, Okla., one-fourth toArleigh R. Patterson, Wilson, kla., and one-fourth to ExplorationConsultants Corporation, Tulsa, Okla., a corpora- .tion of DelawareApplication May 16, 1951,'Serial No. 226,619

4.Claims. (Cl. 255-22 This invention relates to a method of andapparatus for automatically imposing a constant weight on the drill bitof a portable drilling unit.

As it is well known, in. using a-portable drilling unit the bore holesdrilled are usually relatively shallow; therefore, the weight of theKelly bar and drill pipe is frequently insuflicient to press the drillbit downward and provide the desired penetration. It is .then necessaryto place additional weight on the drill bit. This is usuallyaccomplished by .imposing aportion of the weight of the truck anddrilling rig upon the Kelly bar by'the use of pull down chains. Thechains are suitably connected to the top of the Kelly bar and are drivenby a power take-off from the truck engine through the medium of suitablegearing and a manually operated clutch. The pull down chains areoperated as desired by engaging and disengaging the manually operatedclutch. In applying weight to the drill bit in this manner, the drillermust pay constant attention to the drilling operation to operate theclutch and apply and remove weight from the drill bit to precludeoverloading or underloading the drill bit.

The present invention contemplates a novel method of and apparatus forimposing a constant weight on the drill bit of a portable drilling unitduring the entire vertical travel of the Kelly bar made for'each jointof drill pipe used in the drilling operation. The pull down chains aredriven until the rear portion of the truck is raised a predetermineddegree to impose the weight of the truck on the Kelly bar. The pull downchains are then driven in accordance with the downward movement of theKelly bar to retain the truck in a predetermined tilted position,thereby maintaining a uniform weight on the Kelly bar and drill bit. Asone embodiment, it is contemplated to drive the pull down chains by anelectric motor through the medium of a transmission unit. The electricmotor is cont'rolledby a spring urged switchadapted to be automaticallyoperated by a stationary control rod in accordance with the height ofthe truck.

An important object of this invention is to provide a z novel method andmeans for imposing a constant weight on the drill bit of a portabledrilling unit.

Another object of this invention is to increase the efiiciency ofportable drilling units.

A further object of thi's invention is to provide an automatic drive forthe pull down shaft of a portable drilling unit.

' A still further object of this invention is to provide an eflicientpull down drive means which may be economically manufactured,

Other objects and advantages of the'invention will be evident from thefollowing detailed description, read in conjunction with theaccompanying drawings, which illustrate my invention.

In the drawings:

Figure 1 is a schematic rear elevational view of a portable drillingunit.

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Figure'2 is a plan view of the drilling unit shown in Fig. 1 with therig structure removed.

Figure 3 is a wiring diagram of the electrical circuit utilized in oneembodiment of the present invention.

Figure 4 is a cross-sectional view taken on lines 44 of Figure 2.

Referring to the drawings in detail, and particularly Fig. 1, referencecharacter 2 designates the bed portion of a truck supported by a pair ofwheels 4 through the medium of an axle (not shown), axle housing 6 andsprings 7. A rig structure 8 is mounted on the rear portion of the truckbed 2 and has a pair of sheaves 10 rotatably supported in the upperportion thereof. A rotary table 12 is rotatably supported on the truckbed 2 and is adapted to be driven by suitable machinery (not shown) inthe usual manner. Telescopically disposed in the rotary table 12 is aKelly bar 14 for transmitting the rotary motion of the table 12 to thedrill pipe and drill bit (not shown). A plurality of joints of drillpipe (not shown) with a drill bit on the lower end thereof, are securedin tandem relation to the lower end of the Kelly bar 14 in a manner wellknown in the art. A suitable swivel 16 is provided on the upper end 18of the Kelly bar 14 and has a pair of arms 20', usually termed heavenerbars, extending from opposite sides thereof. The swivel 16 permitsrotation of the Kelly bar 14 independent of the heavener bars 20. Aconduit 22 extends upwardly from the Kelly bar 14 and is utilized tosupply drilling fluid to the drill bit in the usual manner.

A pair of chains 24 are suitably secured to the heavener bars 20 andextend downwardly around sprockets 26 mounted on a pull-down shaft 28extending transversely across the truck bed 2. The shaft 28 is rotatablysupported on the truck bed 2 by pillow block type bearings 30. Thechains 24 extend upwardly from the respective sprockets 26 and areconnected at the opposite ends to cables or wire lines 32. The cables 32extend upwardly over the sheaves 10, and then downwardly for connectionwith the heavener bars 20.

An additional sprocket 34 is secured on the pull-down shaft 28 and isinterconnected by a chain 36 (see also Fig. 2) to a sprocket 38 rigidlymounted on another transversely disposed shaft 40. One end 42 of theshaft 40 is rotatably supported by a pillow block type bearing 44 on thetruck bed 2, and the opposite end 46 thereof extends into a suitablegear box 48. The shaft 40 is adapted to be driven, through gears (notshown) in the gear box 48, by a shaft 50 connected to a power take-off(not shown) of the truck engine (not shown). The gears (not shown) inthe box 43 may be any suitable compound gears usually found in "gearboxes for conventional winches, for example, one

small and one large gear forming compound gears. A suitable clutch 52 isinterposed in the shaft 40 to control operation of the sprocket 38.

Ordinarily, when it is desired to place weight on the Kelly bar 14 andhence the drill bit, the driller operates the clutch 52 to causeengagement thereof. Assuming the drive shaft 50 is being rotated by thetruck engine, the shaft 40 will then be rotated to drive the sprocket38. The sprocket 38 drives the sprocket 34, pull-down shaft 28 andsprockets 26 through the medium of the chain 36. It is readily seen thatthe movement of the I sprockets 26 is transmitted through the chains 24(Fig. 1)

and heavener bars 20 to the Kelly bar 14 to move the Kelly bar 14 in adownward direction through the rotary table 12.

In the event the drill bit is operating in a hard formation, the Kellybar 14 will not move downward as fast as the chains 24 are pulled by thesprockets 26. Therefore, the chains 24 will pull upwardly on thesprockets 26 and pull-down shaft 28. Since the pull-down shaft 28 issecured to the truck bed 2 by the bearing units 30, the truck bed 2 willthereby be raised or tilted to impose a portion of the weight of thetruck bed 2 on the Kelly bar 14 and drill bit. When the truck bed 2 hasbeen raised to the desired height, the clutch 52 is disengaged. As thedrill bit penetrates the formation, the Kelly bar 14 and truck bed 2move downward, with a consequent decrease in the application of weighton the drill bit. Obviously, the higher the truck bed 2 is raised ortilted, the greater will be the application of weight on the drill bit.

The present invention contemplates an automatic drive for the pull-downshaft 28 to retain a constant weight on the Kelly bar 14. As oneembodiment, I provide a sprocket 54 (Fig. 2) on the shaft adjacent thesprocket 38. The sprocket 54 is interconnected by a chain 56 to asprocket 58 disposed on the output shaft 60 of a suitable transmission62. The transmission 62 is of the usual type, having forward and reversegears (not shown) as well as a neutral position. Furthermore, thetransmission 62 is secured to the truck bed 2 in any suitable manner(not shown). Another sprocket 64 is secured on the input shaft 66 of thetransmission 62. The sprocket 64 is interconnected by a chain 68 to acomplementary sprocket 70 provided on the drive shaft 72 of an electricmotor 74.

A suitable storage battery 76 provides a source of electrical energy forthe motor 74, and is connected thereto by an electric circuit showndiagrammatically in Fig. 3. One side of the battery 76 is grounded by awire 78, and the opposite side thereof is interconnected by a wire 80 tothe motor 74, with suitable switches interposed therebetween, and asuitable fuse 82 is interposed in the wire 80 to preclude an overloadingof the circuit in the usual manner. Connected in series with the fuse82, and between the battery 76 and motor 74, is a single pole, singlethrow switch 84; in turn connected with a single pole single throwswitch 86 of the push button type, normally closed and having a springreturn; and cooperating with a time delay relay 88; and a solenoid relayall interposed in the wire 80. A short circuiting wire 92 isinterconnected to the wire 80 between the switches 84 and 86, andbetween the time delay relay 88 and the solenoid relay 90 to shortcircuit the switch 86 and relay 88 as will be more fully hereinafter setforth. A suitable switch 89 may cooperate with the relay 90 to provideelectric communication between the battery 76 and the motor 74 in anysuitable manner. is interposed in the wire 92 and is normally in an openposition to preclude the flow of the current through the wire 92. Themotor 74 is grounded by a wire 26 in a well known manner. It will beapparent that the motor 74 receives electric current directly throughthe switch 89 upon actuation thereof by the relay 90.

Referring again to Fig. 2, a suitable switch box 98 is mounted on therear portion of the truck bed 2 convenient to the driller. Anotherswitch box 100 is mounted on the truck bed 2 forward of the switch box98 and directly above the axle housing 6 of the truck. The switch box100 is adapted to contain the fuse 82, switch 86, time delay relay 88,and solenoid relay 90. The push button 102 of the switch 86 extendsabove the switch box 100 as clearly shown in Fig. 4. A vertical controlrod 104 is secured at its lower end to the axle housing 6 and extendsupwardly through an aperture 106 provided in the truck bed 2 adjacentthe switch box 100. A transverse arm 108 is provided on the upper end ofthe control rod 104 in such a position to extend directly over the pushbutton 102. The length of the control rod 104 is preferably adjustable(not A single pole single throw switch 84 Iii) shown) to vary the heightof the arm 108 for purposes as will be hereinafter set forth.

Suitable conduits 110 (Fig. 2) interconnect the motor 4 74, battery 76and switch boxes 98 and 100 to carry the electrical wiring 80 and 92'finthe usual manner.

Operation In utilizing the present pull-down drive, the clutch 52 isdisengaged to permit operation of the shaft 40 independent of theoperation of the drive shaft 50. To place the drive in operation, thedriller simply closes the switch 84 which is located in the switch box98. Since the switch 94 is normally open and the switch 86 is normallyclosed, current will flow from the battery '76 through the wire 80 tooperate the motor 74. The motor 74 in turn drives the transmission unit62 through the medium of sprockets 70 and 64 and chain 68. Assuming thetransmission 62 is set to drive in a forward direction, the sprockets 58will be rotated in the same direction as the sprockets 64 to drive thesprockets 54, shaft 40 and sprocket 38 through the medium of chain 56.The chain 36 will therefore be driven to drive the pull-down chains 24and place a downward pull on the Kelly bar 14 in the same manner aspreviously set forth.

In the event the drill bit is drilling in a hard formation and the Kellybar 14 will not move down at a suificient rate of speed, the pull-downchains 24 will exert an upward pull on the truck bed 2 through themedium of the sprockets 26, shaft 28 and bearing units 30. The rearportion of the truck bed 2 will thereby be raised to tilt the truck in aforward direction and impose a portion of the load of the truck on theKelly bar 14 and drill bit. The large and small compound gears (notshown) provided in the gear box 48 prevents any unwinding of the pulldown chains 24. As his well known, the truck springs 7 will permit avariable amount of upward movement of the truck bed 2 independent of theaxle housing 6 and wheels 4. Therefore, as the truck bed 2 is raised ortilted by the pull-down chains 24, the push button 102 (Fig. 4-) will bemoved upwardly toward the arm 108 of the stationary control rod 104. Thearm 108 will thereby, in effect, depress the push button 102 when thetruck bed 2 has been raised a predetermined degree to open the switch 86and disrupt the supply of electrical energy to the motor 74;. The motor74 will then become inoperative and stop further movement of thepull-down chains 24. The chains 24, being secured at one end to theheavener bars 20 and secured at their opposite ends to the cables 32which are in turn secured to the heavener bars 20, will retain the truckbed 2 in a fixed position relative to the Kelly bar 14.

As the drill bit penetrates the formation, the Kelly bar 14 and truckbed 2 will move simultaneously in a downward direction. The push button102 will thereby be moved downward away from the arm 108. Since theswitch 86 is of the spring return type, the push button 102 will beautomatically raised when released by the arm 108 to close the switch 86and again permit a fiow of electrical energy to the motor 74. The motor74 will then again drive the pull-down chains 24 and raise the truck bed2 until the push button 102 is actuated by the I arm 108.

0 stant weight is retained on the drill bit. The time delay relay 88 maybe set to operate atany desired speed, and is utilized to reducevibrations in the truck bed 2 due to the frequent operations of theswitch 86. I

When the Kelly bar 14 has been moved downward the desired degree, thetransmission unit 62'is placed in reverse to drive the pull-down chains24 in an opposite direction and raise the Kelly bar 14 through themedium of the cables 32 and heavener bars 20. An additional joint (notshown) of drill pipe may then be secured to the Kelly bar 14 and thedrilling operation repeated. The switch 94 may be closed when thetransmission 62 is placed in reverse to short circuit the switch 86 andtime delay relay 88 and expedite the raising of the Kelly bar 14.Furthermore, the switch 94 may be utilized during the drilling operationin the event the switch 86 or time delay relay 88 become inoperative.The operation of the pull-down chains 24 will then be manuallycontrolled by the driller.

From the foregoing, it is apparent that the present invention provides anovel method of and apparatus for imposing a constant weight on thedrill bit of a portable drilling unit. The truck on which the unit ismounted is tilted a predetermined degree with a portion of the truckweight imposed on the Kelly bar, and is retained in a predeterminedtilted position, to impose a constant weight on the drill bit. The drivefor the pull-down shaft is fully automatic to materially increase theefficiency of the entire drilling unit. It is also apparent that thepresent invention provides an efficient drive means that may beeconomically manufactured.

Changes may be made in the combination and arrangement of parts asheretofore set forth in the specification and shown in the drawings, itbeing understood that any modification in the precise embodiment of theinvention may be made within the scope of the following claims withoutdeparting from the spirit of the invention.

I claim:

1. A pull-down drive for a drilling apparatus disposed on a truck andincluding a Kelly bar, pull-down chains for tilting the truck andimposing the weight of the truck on the Kelly bar, an electric motor fordriving the pulldown chains to cause a tilting of the truck, a source ofelectrical energy, transmitting means for transmitting electrical energyfrom said source to the motor, and means for automatically connectingand disconnecting said transmitting means in accordance with the tilt ofthe truck, to provide an essentially constant angle of tilt of the truckand uniform weight on the Kelly bar during operation of the drillingapparatus.

2. A pull down drive for a drilling apparatus having a Kelly bar andmounted on a truck, pull down chains for tilting the truck and imposingthe weight of the truck on the Kelly bar, an electric motor drivinglyconnected to the pull down chains to cause the tilting of the truck, asource of electrical energy, an electrical circuit interconnecting themotor and said source for energizing the motor, a switch in theelectrical circuit, stationary means carried by the truck, said switchbeing responsive to the angle of tilt of the truck for alternateengagement and disengagement with the stationary means to maintain thetruck at a substantially uniform angle of tilt and impose a uniformweight on the Kelly bar during operation of the drilling apparatus.

3. A pull down drive for a drilling apparatus having a rotatable Kellyand mounted on a truck, pull down chains mounted on the truck, a powerunit for driving the pull down chains providing for a tilting of thetruck and imposing the weight of the truck on the Kelly, a source ofenergy for the power unit, means for supplying energy from said sourceto the power unit, control means carried by the truck and connected tosaid supply means normally providing a flow of energy to the power unitfor operation of the pull down chains, rod means carried by the truckfor cooperation with the control means, said control means beingresponsive to the tilt of the truck and adapted to engage the rod meanswhereby the supply of energy to said power unit is caused to bedisrupted.

4. An automatic pull down drive for a drilling apparatus having arotatable Kelly bar, pull down chains mounted on the truck, an electricmotor for driving the pull down chains to provide for tilting andimposing the weight of the truck on the Kelly bar, a source ofelectrical energy, a circuit connecting said source to the motor, aspring urged switch interposed in the circuit and normally in closedposition to provide for a flow of energy to the motor, a stationary rodcarried by the truck, switch means carried by the truck and responsiveto a predetermined tilted position of the truck to engage the rod tocause a disruption of the flow of energy to the motor, and a time delayrelay in the circuit for delaying operation of the switch and dampeningvibration of the truck,

References Cited in the file of this patent UNITED STATES PATENTS2,005,122 Young et al June 18, 1935 2,080,804 Brantly May 18, 19372,128,650 Knoerzer Aug. 30, 1938 2,458,241 Beck Jan. 4, 1949 2,516,182Bury July 25, 1950 2,594,098 Vanderzee Apr. 22, 1952

